Right, but someone possibly suggested at 2 micron for the Racor, so I would think putting a 2 micron filter at the Racor primary would be self-defeating. Wouldn't it clog up the Racor prematurely, while essentially rendering the secondary 10 micron spin-on worthless?
In any event, I have enjoyed the elimination of a secondary spin-on on my coach and the replacement of the Racor with a Davco unit. It still gives 10 micron protection while being a whale of a lot easier, less messy, and cheaper, to change.

FWIW: I wouldn't go as tight as a 2 micron in this setup. Only in a warm climate and on a system with a lift pump ( filter on pressure side) and carry spares.

Well we do have some members running 2 micron and don't seem to be a problem. I had a 2 micron I had got somewher and I picked up a 10 micron this morning. I installed the 2 to see how long it will run with out gage rise to red.

BTW,, the 2 micron is what the fuel polisher are using. So I am just going to polish my own.
Let you know how it works.